package com.example.goodog;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.HashMap;
import java.util.Stack;

import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.widget.ImageView;

public class ImageLoader {
	
	private HashMap<String, Bitmap> cache=new HashMap<String, Bitmap>();
	private File cacheDir;
	Context context;
	
	public ImageLoader(Context context)
	{
		this.context = context;
		
		photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1);
		
		if (android.os.Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED))
			cacheDir=new File(android.os.Environment.getExternalStorageDirectory(),context.getString(R.string.cache_dirname));
		else
			cacheDir=context.getCacheDir();
		
		if(!cacheDir.exists())
			cacheDir.mkdirs();
	}
	
	final int stub_id=R.drawable.icon;
    public void DisplayImage(String url, Activity activity, ImageView imageView)
    {
    	if(cache.containsKey(url))
    		imageView.setImageBitmap(cache.get(url));
        else
        {
            queuePhoto(url, activity, imageView);
            imageView.setImageResource(stub_id);
        }    
    }
        
    private void queuePhoto(String url, Activity activity, ImageView imageView)
    {
        photosQueue.Clean(imageView);
        PhotoToLoad p=new PhotoToLoad(url, imageView);
        synchronized(photosQueue.photosToLoad){
        	photosQueue.photosToLoad.push(p);
        	photosQueue.photosToLoad.notifyAll();
        }
        
        if(photoLoaderThread.getState()==Thread.State.NEW)
            photoLoaderThread.start();
    }
    
    private Bitmap getBitmap(String url) 
    {
    	String filename=String.valueOf(url.hashCode());
    	File f=new File(cacheDir, filename);
    	
    	Bitmap b = decodeFile(f);
    	if(b!=null)
    		return b;
        
        try {
            Bitmap bitmap=null;
	        InputStream is=new URL(url).openStream();
	        OutputStream os = new FileOutputStream(f);
            Utils.CopyStream(is, os);
            os.close();
            bitmap = decodeFile(f);
            return bitmap;
        }
        catch(MalformedURLException e)
        {
        	Bitmap bookDefaultIcon = BitmapFactory.decodeResource(context.getResources(),
                    R.drawable.icon);
        	return bookDefaultIcon;
        }
        catch (Exception ex){
           ex.printStackTrace();
           return null;
        }
    }

    private Bitmap decodeFile(File f){
    	try {
    		BitmapFactory.Options o = new BitmapFactory.Options();
			o.inJustDecodeBounds = true;
			BitmapFactory.decodeStream(new FileInputStream(f),null,o);
			
			final int REQUIRED_SIZE=70;
			int width_tmp=o.outWidth, height_tmp=o.outHeight;
			int scale=1;
			while(true){
				if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
					break;
				width_tmp/=2;
				height_tmp/=2;
				scale++;
			}
			
			BitmapFactory.Options o2 = new BitmapFactory.Options();
			o2.inSampleSize=scale;
			return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
		} catch (FileNotFoundException e) {}
		return null;
    }
    
    private class PhotoToLoad
    {
        public String url;
        public ImageView imageView;
        public PhotoToLoad(String u, ImageView i){
        	url=u; 
        	imageView=i;
        }
    }
    
    PhotosQueue photosQueue=new PhotosQueue();
    
    public void stopThread()
    {
    	photoLoaderThread.interrupt();
    }
    
    class PhotosQueue
    {
        private Stack<PhotoToLoad> photosToLoad=new Stack<PhotoToLoad>();
        
        public void Clean(ImageView image)
        {
            for(int j=0 ;j<photosToLoad.size();){
                if(photosToLoad.get(j).imageView==image)
                    photosToLoad.remove(j);
                else
                	++j;
            }
        }
    }
    
    class PhotosLoader extends Thread {
        public void run() {
        	try {
	        	while(true)
	        	{
		        	if(photosQueue.photosToLoad.size()==0)
		        		synchronized(photosQueue.photosToLoad){
		        			photosQueue.photosToLoad.wait();
		        		}
		            if(photosQueue.photosToLoad.size()!=0)
		            {
		                PhotoToLoad photoToLoad;
		                synchronized(photosQueue.photosToLoad){
		                	photoToLoad=photosQueue.photosToLoad.pop();
		                }
		                Bitmap bmp=getBitmap(photoToLoad.url);
		                cache.put(photoToLoad.url, bmp);
		                if(((String)photoToLoad.imageView.getTag()).equals(photoToLoad.url)){
		                    BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad.imageView);
		                    Activity a=(Activity)photoToLoad.imageView.getContext();
		                    a.runOnUiThread(bd);
		                }
		            }
		            if(Thread.interrupted())
		            	break;
	        	}
        	} catch (InterruptedException e) {
 			}
        }
    }
    
    PhotosLoader photoLoaderThread=new PhotosLoader();
    
    class BitmapDisplayer implements Runnable
    {
        Bitmap bitmap;
        ImageView imageView;
        public BitmapDisplayer(Bitmap b, ImageView i){bitmap=b;imageView=i;}
        public void run()
        {
            if(bitmap!=null)
                imageView.setImageBitmap(bitmap);
            else
                imageView.setImageResource(stub_id);
        }
    }

	public void clearCache() {
		cache.clear();
		
		File[] files=cacheDir.listFiles();
		for(File f:files)
			f.delete();
	}

}
